film clearing time in fixer

Discussion in 'B&W: Film, Paper, Chemistry' started by archer, Jul 12, 2009.

  1. archer

    archer Member

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    As is my custom when trying a new film, I fix a sheet of each new film I'm testing to see how long it takes to clear the undeveloped, fully exposed film in my standard fix which is based on hypo thiosulfate. The two Arista EDU Ultra films, 100asa and 200asa, cleared completely in 2.5 min. but the Efke 50asa took a full five minutes to clear completely. Can anyone tell me why the slower film took so much longer to clear? I'm assuming that the older emulsion form of the Efke has something to do with it but why?
    Thanks for the help,
    Denise
     
  2. dancqu

    dancqu Member

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    I really suspect you've some defective Efke film.
    There is no GOOD reason why a slower film
    should take 100% more time to fix than
    some medium speed films. Dan
     
  3. jeroldharter

    jeroldharter Member

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    I assume you were using a fresh batch of fixer?
     
  4. Ian Grant

    Ian Grant Subscriber

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    Most likely a fixer problem, I've used EFKE films for over 30 years and the fix normally.

    But then 5 minutes isn't that long for a non rapid Sodium Thiosulphate (hypo) fixer.

    Ian
     
  5. Jeff Kubach

    Jeff Kubach Member

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    Normally it is usually 2-4 minutes to fix, dependly on how good the fix is. 5 minutes is a on a long side but not uusally so.

    Jeff
     
  6. Ian Grant

    Ian Grant Subscriber

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    Iford's recommended fixing time for films in a simple Metabisulphite/Sodium Thiosulphate fixer IF-2 was 10 to 20 minutes, so a clearing time of 5 minutes is well within expectations.

    Ian
     
  7. Jeff Kubach

    Jeff Kubach Member

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    Thanks Ian, I didn't realized that. :D

    Jeff
     
  8. Christopher Walrath

    Christopher Walrath Member

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    Wirelessly posted (BlackBerry9000/4.6.0.167 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102 UP.Link/6.3.0.0.0)

    Efke 25 is three minutes for me in fresh stew.